This invention relates generally to novel and improved brake equipment for rail vehicles and more particularly to a single handle computer controlled propulsion and brake equipment located on the locomotive and arranged to control the propulsion of such locomotive and any trailing locomotive and the application and release of the brakes of such locomotive, any trailing locomotive, and any cars coupled to either.
Prior art brake equipment for locomotives has typically been implemented with mechanical and pneumatic hardware, as, for example, the 26-L brake equipment of New York Air Brake Company of Watertown, N.Y. As illustrated in FIG. 1, this prior art brake equipment employs as major components a 26-C brake valve 30 including an independent brake valve SA-26, a 26-F control valve 33 and a J relay valve 37 interconnected with various pneumatic pipes represented by solid lines. The brake valve 30 responds to movement by the train operator of an automatic brake handle 31 to regulate pressure in a brake pipe 40 by means of an equalization reservoir 36 and a brake pipe relay in the brake valve 30 for application and release of brakes on the locomotive, the brakes of any trailing locomotive and the brakes of cars coupled to either (train brakes).
The automatic brake handle has six positions as illustrated by the sector diagram in FIG. 2 and defined as follows:
a) The Release position is for charging the brake equipment and releasing the train brakes. PA1 b) In the Minimum Reduction position, brake pipe pressure is reduced a minimum amount so as to initiate quick service on the train brakes (typically 4-6 psi brake pipe reduction), and lightly apply the train brakes. PA1 c) The sector or zone between the Minimum Reduction and Full Service positions is the service zone. As the automatic brake valve handle is moved through this zone from Minimum Reduction toward Full Service, brake pipe pressure is reduced proportionally to 23-26 psi with the handle at the Full Service position, a full service brake application is obtained. PA1 d) In addition to providing full service brake application as with the brake valve handle in the Full Service position, Suppression of overspeed control and safety control application is obtained in the suppression position. PA1 e) The handle is movable to the Handle Off position as for trailing units of a multiple unit locomotive or for locomotive's being towed "dead" in a train. The handle off position is also used for "over-reductions" allowing brake pipe to be reduced further than attainable in the Full Service position. Thus assuring full train brake applications. PA1 f) The Emergency position is used for making brake valve emergency brake applications and results in brake pipe exhaust and brake pipe venting at the highest rate of reduction.
The brake valve 30 also responds to movement of an independent brake handle 32 by the train operator to control the application and release of the locomotive brakes independently of the train brakes and for releasing an automatic brake application of the locomotive independently of the train brakes by way of the 26-F control valve 33 and the J relay 37.
The independent brake handle 32 has two extreme positions, Release and Full Application separated by an application zone as shown in FIG. 2. As the handle is moved from the Release position through the application zone toward the Full Application position will apply the locomotive brakes. The independent handle 32 can be depressed so as to cause the release of any automatic brake application existing on the locomotive (due to operation of the automatic brake handle 31). This is effected via the 26-C brake valve 30 and the 26-F control valve 33. If the independent brake handle 32 is in an Application position, the locomotive brake will be applied according to the higher of independent or automatic brake.
The 26-F control valve 32 and auxiliary reservoir 36 respond to service and emergency rates of brake pipe pressure reduction (brake applications) to control the locomotive brake cylinder pressure via the J relay valve 37. The 26-F control valve 33 also responds to a brake release operation of the independent brake handle 32 to control locomotive brake cylinder pressure to release the locomotive brakes following an automatic brake operation at the service rate developed by operation of the automatic brake handle 31. A key element of the 26-F control valve 30 is a double check valve 34 which applies to the J relay valve 37 the higher of the pressures developed by the 26-F control valve 33 or by the independent application and release pipe 42.
The J relay valve 37 is a volume amplifier that operates to translate the pressure at a smaller volume input to a desired pressure at a larger volume output. As the desired output pressure can differ for different locomotive (different sized brake cylinders), it has been necessary to select a particular J relay valve for a Particular locomotive specification.
The P2-A valve 35 is a brake application or penalty valve responsive to unsafe conditions to effect brake application at the full service rate. For instance, the P2-A valve is illustrated as responding to an overspeed condition and/or to a foot pedal fault (absence of foot pressure on the foot pedal).
The brake equipment also includes a multiple unit valve 38 enabling the locomotive to be united with other locomotives as either a lead, trail or dead unit. The multiple unit valve 38 of a lead unit serves to signal trail units via independent brake application and release pipe 42 and an actuating pipe 43. In the lead position, multiple unit valve 38 connects the actuating pipe signal from brake valve 30 to the control valve 33 and actuating pipe 43 and connects the independent application and release signal from the brake valve 30 to the independent application and release pipe 42.
FIG. 2 also illustrates the third master control stand handle 39 which is the throttle for controlling propulsion and dynamic braking over the 27-wire trainline. The throttle 39 includes the standard 1 to 8 propulsion positions as well as the dynamic braking which goes from a set position to a maximum. Between the propulsion and the dynamic braking portion is the Idle position and a Stop Engine off position. The throttle lever 39 provides an analog output signal proportional to handle position with the maximum output representing maximum power. The throttle 39 is shown as a single handle for both the propulsion and the dynamic braking and is the subject of a copending patent application, but is generally two separate handles in other prior art systems.
The prior art brake equipment is costly to manufacture as it requires substantial iron and aluminum castings for each of the pneumatic valves and is costly to install as it requires numerous pipe interconnections.
Computerized brakes are well known as shown by U.S. Pat. No. 4,402,047 to Newton et al. In this computerized brake control system, the computer calculates the desired brake cylinder pressure from commanded brake signals, vehicle weight, vehicle speed and dynamic braking and compares the desired brake cylinder pressure with the actual brake cylinder pressure. Then it controls the fluid brake system to cause the actual brake pressure to be substantially equal to the desired brake pressure. As illustrated at instruction 338 in FIG. 2 of that patent, the desired brake pressure BCD is equal to the dynamic feedback signal DBC divided by 100 times the desired braking signal BCC. Also as shown at instruction 146 of FIG. 3B, the final desired braking pressure BCF is equal to the load compensated commanded braking pressure BCC minus the speed component BCS minus the dynamic braking component BCD. The analog input signals come from the standard control handles similar to those shown in FIG. 2 herein.
Another system which shows the use of of a computer to control magnetic valves for applying and releasing brake pressure is U.S. Pat. No. 4,652,057 to Engle, et al. A single control handle 76 is used in combination with a control panel 102 and a display 96. The computer provides the appropriate dynamic and fluid brake signals as a function of the position of the control handle 76. Initially, dynamic brakes are applied and augmented by fluid brakes if one or more of the dynamic brakes fail. This system is designed specifically for an integral train where the number of cars per locomotive are fixed and the braking capacity of the cars and the locomotive are known. This system is similar to the systems on mass transit trains using a single handle for propulsion and braking.
In conventional locomotive operation the number and type of locomotives used in a train vary and thus the dynamic braking capacity varies. Also, the number of cars in the train vary widely and have no direct correlation to the number of locomotives. Thus, the engineer or operator must control the level of dynamic and train or fluid braking separately to his satisfaction.
Thus it is an object of the present invention to provide a single control handle for all types of trains and locomotives.
Another object of the present invention is to provide a single handle computerized control system which allows the type of operator control of a plural handle system.
These and other objects are achieved by providing a single handle movable between a maximum propulsion position, through diminishing propulsion positions, through a release/idle position, through increasing braking positions, through a full service brake position to an emergency brake position. A control system receives position signals from the handle and generates propulsion, dynamic braking and fluid braking control signals as a function of the position signals. For any braking position of the handle, the control system first applies or removes dynamic braking and then provides fluid braking depending upon the position of the handle, the type of train brakes and whether the dynamic braking has maximized or is zero. Thus, when the handle position assumes an initial braking position, the control system generates a dynamic braking signal and generates a fluid braking signal if necessary for the braking position.
When the handle assumes the next braking position less than the previous braking position, the control system generates a dynamic braking signal with smaller value than the dynamic braking signal of the previous braking position. On train systems which have a graduated release, when the next braking position is less than the previous braking position, the control means generates a dynamic braking signal of a smaller value than a dynamic signal of a previous braking position until no braking signal is generated and generates a fluid braking signal of a smaller value than a fluid braking signal of the previous braking signal after no dynamic signal is generated for the next braking position. In freight trains, for example, where the fluid brakes do not have a graduated release, the control system generates a dynamic braking signal of smaller value than a dynamic braking signal of the previous braking position until no dynamic braking signal is generated and generates a fluid braking release signal of a smaller value than a fluid braking signal of a previous braking position only when the handle is in the release/idle position.
For an initial braking position or a next braking position greater than a previous braking position, the control system generates a dynamic braking signal until maximum value of the dynamic braking signal is generated and generates a fluid braking signal after the maximum value of the dynamic braking signal is generated. Preferably, the handle includes dynamic braking range positions increasing from the release/idle position to a full dynamic braking position and a fluid braking range of positions increasing from the full dynamic braking position to the full service braking position. The handle would include a detent at the full dynamic braking position to allow the operator to feel when they have gone from the dynamic braking to the fluid braking position. Thus for the initial braking, the operator can apply either just dynamic braking or dynamic braking in combination with fluid braking. Similarly, for subsequent braking, the operator will also know when the fluid braking takes effect. Thus the handle becomes position sensitive until the handle has left the dynamic braking zone and entered the fluid braking zone. Thereafter, for any decreases the dynamic braking is decreased and for any subsequent increases the dynamic braking is reapplied until it has reached its maximum value.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.